Radiocondenser



Feb. 16 1926. 1,573,374

P. A. CHAMBERLAIN RADIOCONDENSER Filed July 2, 1924 3 Sheets-Sheet 1Feb. 16 1926.v

P. A. CHAMBERLAIN RADIOCONDENSER Filed July 2,

5 Sheets-Sheet 2 Y/l/l/l/l//ll/A l;

Z?? fo 7j inde/LZ( (canberZZl Feb. 16 1926.

P. A. CHAMBERLAIN RADIOCONDENSER Filed July 2, 1924 3 Sheets-Sheet .'5

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Patented Feb.- 16,'v 192e.

. `1,573,374 PATENT OFFICE.

:PAUL A.. CHAMBERLAIN, OF CHICAGO, ILLINOIS, ASSIGNOR, BY DIRECT ANDMESNE ASSIGNMENTS, TO ELECTRICAL DEALERS SUPPLY HOUSE, INC., O IFCHICAGO, ILLI- NoIs, A CORPORATION OF ILLINOIS.

RADIOCONDENSER.

Application led July 2,

in multiple circuit controlling devices for radio apparatus and moreparticularly to condensers adapted for use in multiple circuits and hasfor its principal object to provide an improved form of apparatus of theclass described'inwhich two orm'ore condensers each coupled in aseparatecircuit, as for'ins'tance, in successive amplification stagesofa'radio receiving or sending set, may. bei all adjusted-and therespective circuits bal'anced so as'to afford lsimultaneous control ofthe circuits by manipulation -of` a single controlling -memben For thepurpose of illustrating vmy im'- proved apparatus, I have shown it asapplied to a 'standard hook-up for amplification of radio-frequencycurrents vin a radio receiving set in which the separate audionamplificationv circuits are tuned by varying the capacities of each gridcircuit. It is well known by those vfamiliar* in. the art'vthat theadvantages v'of ,controlling such "coul densers by' a singlecontrolling-device are self evident, yet 'it 'has' been found quitedifficult to produce satisfactory, unitary control apparatus -of thischaracter in commercial quantities vfor thereason that severalvariable-and-uncertain factors are established Yduring construction of eachapparatus'. Awhich factors are not subjecttoready control ormeasurement,even.though great care be exercised to' conform *to uniformspecifications and st andardsof construction. These factors will behereinafter more fully discussed in connection with'my improved meansand method of;v` offsettingthe combined -effects ofsuch factors'.l

My invention contemplates the provision of a novel arrangement of.circuitsv and method of"adjust1ng the same, whereinmeans are providedfor independently A'adjusting the vca acitieso-f a plurality ofcondenserunits w ich adjustment is made after the apparatus is wired andcompleted so that the circuit condensers and theirrc- 1924.- serial No'.72213617',`

spective circuits are balanced Or phased to the same periodicity withrespect to each other. This'balancing of the several capacities willoffset the combined effects of the several uncertain and variablefactors already suggested. Another-feature of the invention is theprovision Ofnneans for shielding the several condenser units from eachotherthereby permitting such units to be mounted in relatively' closerelationship with each other, as for instance, in axial alignment .witheach other on a common shaft, thereby eliminating the effect of.

capacity coupling between the separate circuits a't this point.

rlhe invention -may be best understood by reference to thev accompanyingdrawings in which: i

Figure 1 iis-a plan View of Oneform of condenser construction inaccordance-with `my invention.

i Figure 2 is-a sideview of the condenser shown in Figure l. i

Figure 3 is an end view of the condenser shown in Figure l with a partbroken away to show oneend of .a shielding plate. i

Figure 4 is a section taken on. line 4 4 of Figure 3..

Figure 5 lis .a planl view' of a vmodified form of condenser in thisform thebalance and shield adjusting plate is movable with the roller. l

Figure 6V is an end viewof the condenser shown in Figure 5.

- Figure 7' is a detailtaken lon line 7-7 of Figure 5.

Y Figure 8-is a diagram nshowing a typical application "of my inventionto'a portion of a radio frequency'4 amplification apparatus.

Figg) is an enlarged diagram of the condenser construction.

Referring -now` tof details shown on the drawings, Figs@ todillustrateya preferred form of-condenserwhich 4may be used 1n carryingout my Inventlon'. This condenser comprises a frame consisting of metalend lms ' condenser units; in the ornrillustratcd here# necting membercomprising rodll secured to the end plates by screws 17, .-17. The.structure is provided. with a plurality of in two such condenser units18 and 19 aref/shown, the firstof ,which consists of a stator made up ofa plurality of parallelly disposed plates 21', 21 spaced apart, andarotor element'made up of a plurality of plates 23, 23 interposed betweenadjacent 'stator plates. This'condenser unit thereforefcomprises an Aairgap condenser of the usual construct-ion,l the stator plates beingsubstantially' rectangular and y the rotor plates .being semi-circulanin shape. The rotor plates are rotated so vas to vary the capacity ofthe condenser in 'the usual manner. The second unit 19' consists of asimilar `arrangementof stator plates 25 'and rotorVv plates-2 6. v'Inthe form of condenser shoivn in figure, the stator plates '21, 21-ofcondenser i gagement fr alimited portion thereof,.as

for instance, adjacent the sides of-the blocks, While the intermediateportion of said-l supi porting rod is reduced in diameter as indicatedat' 33;thus providing a limited contact between the supporting rod andthe insulating'block-to reduce electrostatic losses between thestator-platesand the frame to a minimum. The stator plates may besupportedvon the insulator blocks 30-30 by any suitableF neans, 'forinstance, in Fig. 3, it

l will-be seen that said plates are's'ecured to pieces 34, 34 ofconducting material, 'as for instance by welding, said block piecesbeing vmounted on the inner faces 'of the insulator `30 30 by means ofscrews S5-35. Terminals 36-36 provide connection for the respectivestator velements of condenser units 18 and 19.

i The rotor plates of condenser units 1 l and 19 are mounted on thecommon shaft 4.0v inthe usual 'mannerand the" shaft has bearing in endplates 10 and 11 by'any suitable means, as, for instance, the bearing onplate- 10'consists of a. ball bearing 41 adjustable by a screw 42, whilethe opposite end of the Ashaftis provided with aA split threaded bear.

ing 43 adjustable bva nut 44 to vary the tension on the shaftin the`usual manner.

The shaft .isprovided by a prolongation 45 Y adapted to extend through apanel 46 in the usual manner for connection to a dial or similar manualadjusting device.

'Referring noW "to theparticular features `of novelty forming a` part ofmy invention,

"it will be observed that I provide an electrostatic balancingadjustment between adjacent condenser units. The balancing meansconsists of a pair of' plates50 and 51, interposed between and'adjustable toward and awayA from the plates of the adjacent condenserunits I8 and 19.` vIn the form shown in Figures 1, 2 and 3, .thesebalancing plates are substantially the same as the rotor plates ingeneral outline and are given their lateral adjustment by thumb screwmountings at opposite sides of the condenser. These '-mountings consistherein of a pair of thumb.

screws 52-52 threaded on the supporting rods 31, 31 and having annularslots 53, 53 in which recessed portions 54 yof the balance plates arecarried. As will be' seen from the drawings,x the plate`50, may be movedtoward and-.Naway from theadjacent condenser unit 18 as desired, Whilethe other plate 51 shunt condensers. In the particular 'dia-v gramillustrated, I have shown connections for portions of two stages ofradio-frequency amplification. The grid circuit of the first stageincludes the grid 60 in an audion 61, a grid lead 62 to asecondary coil63 of an input-transformer 59. A grid return lead 64 connects saidsecondary coil to a negative filament lead 65 of audion filament 66.This negative lead connects with the .negative si'de of A battery 67 andmay also go to ground 68. The plate circuit of the first audionincludesy the plate 70 and its ,lead 71 to primary 72 of transformer 73, thence by lead 74 to plus side of A battery 67 through B -battery 75.The filament 66 connects with plus A battery throughv rheo-r stat 78 andleads 77 and .79. The second audion 80 has similarly 'arranged grid and4-lead 82, and grid return 83. The plate circuit constitutes an outputin the usual manner.

type of condenser units will scribed.

One of the commonly used methods of now b e de- The use and applicationof the improved tuning successive amplifying stages as hereinillustrated isby means of c ondensers shunted from the grid lead to thegrid return lead of each grid circuit. j

Among the principal factors which have been-shown to effeetthe tuning ofthe separate circuits are (a) the electrostatic capacity of eachcircuit. This depends upon the relation of the several leads and otherparts of the circuit and may vary considerably as between circuits, eventhough conL electromagnetic effects in each stage caused by the relationof coils and leads thereof either in the grid circuit, plate circuit, orboth circuits of each stage. (d) There is furthermore, electromagneticcoupling between adjacent stages which has considerable effect invarying the inductances of the several stages. (e) There also may bevariations due to differences or defects in the apparatus employed insuccessive stages, including the differences in capacity of audions,thus making it extremely diicult to assure the desired.V uniformcapacity and inductance values to be controlled by the condensers.Capacities of the condensers themselves may vary somewhat. (f) The'resistance values may also vary considerably as between separatecircuits or stages, as, for

vinstance, in the case of defective connections,

contacts, etc. Furthermore, experience demonstrates that it is extremelydiflicult to den tect the controlling elements which cause these variousdifferences in each particular instance.

From the above discussion of the many variable factors, it will be nowunderstool why it is generally considered impracticable to control allof these factors with such de# gree of certainty as to insure uniform4changes in several condenser units used to tune the separate circuitsof the apparatus, even though \these condensers be exactly equal incapacity. In other words, it has been demonstrated that these factors.are established during the manufacture of the apparatus, and vary sogreatly with each set, that it has been found. practically impossible tosecure substantial uniform tuning effects in the separate circuits byvarying separate condensers uniformly, even though the condensers are'Aof substantially the same capacity.

F or these reasons it has usually been `the practice to tune each ofsuch amplification stages by means of independently operated condensers.

M v Improved form of condenser includingr balancing and shielding meansas described is designed to provide an. adjustment to readily compensatefor the varying factors above discussed. In the typical circuit shown inFigure 8 this is accomplished as follows:

The stator of condenserl unit 1S is connected by lead 86 to grid lead 62of the first amplifying circuit, and the second condenser unit 19 isconnected by lead 8T to grid lead 82 of the second amplifying circuit.The rotor 40 of the condenser is connected through lead l to the gridreturn lead Gl which is inl turn connected to both minus filament leadsof the two amplifying stages. Since the grid return lead 83 is alsoconnected to the second minus filament lead, the rotor thus provides acommon connection t-o the two grid return leads, andfurther-4 more,provides a common ground at 68, when such ground connection is used.

New, when the circuit is fully completed, the inductance and capacityvalues of the first and second stage grid circuits usually vary fromtheir desired equal ratios, due to the effect of the several factorshereinbefore discussed. By the provision of the adjustable balancingplates and 51, however, the relative capacities of the two condenserunits and their respective circuits may be balanced to approximateequality, and thus bring their respective circuits int-o phase orresonance at all points of tuning by various means, the simplest methodbeing that of tuning the set to receive a given signal, and thenadjusting the two balancing plates so that the critical point of maximumtuning of each circuit coincide at oneposition of the rotor. In otherwords, said plates are adjusted so that the points of maximum volume ofthe separate amplifying stages are coincident on the single tuning dialof the condenser. This adjustment may be readily made by anyone skilledin the art, and once made, no further adjustment is necessary for allranges of the two condenser units, so long as the internal capacity andinductance values of the separate circuits remain unchanged. Thissemi-permanent adjustment of capacities of the two condenser units 18and 19 is indicated in Figure 8 by the dotted arrows, while the fullarrow indicates that the entire condenser including said units 18 and 19may be Varied by a single adjusting means such as a dial, to tune theset to various, frequencies or lwave manner.

In the enlarged diagram 1n Figure 9 the lengths in the usualconstruction of the condenser is illustrated in greater detail showingdiagrammatically the arrangement of the separate elements of thecondenser units 18 and 19 including the rotor plates, stator plates andbalancing plates.

'mon rotorshaft is employed, and it is desired that the overall lengthof the condenser be restricted tocompact limits.

In the form shown in Figures 5 and 6, I have shown a modified Vform 'ofcondenser which may be used in carrying out my invention.

In this form, the balancing plates are carried upon the rotor instead ofbeing carried upon the condenserframe as in the first form hereindescribed.

Inthe second form'of condenser, the

frame comprises a pair of' insulated or non-l conduc't'ing end plates 90and 91. The condenser units 18*` and 19a each comprises stator plates94, 94 supported n spaced relation on a plurality of supporting bars 92and 95. The bars 92 are supported on the end plate 90 and the oppositebars 95 are supported on. end plate '91.- In this form of condenser' thecondenser units are insulated from each other by providing insulatingmembers, 96, v96, .in alignmentl with each pair of supportingr bars 92and 95. These bars have reduced end portions 92a and 95a extending intheopposite ends of the holes 9.8 in the insulating members and spacedapart therein, as shown in Figure 7. The entire frame is clampedtogether by a securingr means such as rods 99, 99 spaced from the statorplates as best shown 4in Figure 6. The rotor comprises two sets of rotorplates v100 and 101 ofthe usual semi-circular form carried on the shaft40a,

in the usual manner. A These sets of rotor plates are interleaved withthe ystator plates of the respective condenser units 18a and 19a in `theusual manner. The balancing plates a and 51aL are mounted forlongitudinal adjustment on the threaded portion 107 of the yshaft 40aintermediate the con-l denser units 18a and 19, This adjustment isafforded byv suitable means such as threaded members 97, 97 and locknuts 108, 108 associated therewith. In this form of condenser thebalancing plates are preferably circular inshape as shown, inasmuch asthey are movable with the rotor and itV is. desirable -to have theseplates interposed between adjacent stator lplates in all positions ofthe/'rotor so as to provide uniform capacity coupling between saidplates and condensenunits as well as the desired shielding ofthecondenser units from leach other. It will be manifest that in caseonly two circuits, including their respective condenser units, areemployed, the desired balancing may be accomplished as between the twounits by the use of a single balancingseparate `condenser units having acommon rotorand all controlled by al single dial, but with balancingplates interposed between each pair lof adjacent condenser units foradjusting the respective values, in the manner already described inconnect-ion with two such condenser units.

It will be understood that my invention is not limited to the tuning ofsuccessive grid circuits as illustrated herein, but is capable of theuse in many variations of radio apparatus, in which it is desiredi tovary several capacities in substantially uniform decrements, whilecompensating for the uncertain variable factors of distributivecapacity, etc., established in the manufacture of each set. l

I claim:

1. In an apparatus of the class described, a condenser provided withcapacity elements movable relative to each other, one of said elementscomprising a plurality of insulated units, andI means interposed betweenadjacent units and conductively connected to the'other of said elements,and adjustable 'inposition relative to saidinsulated units to vary theirrespective capacity, ratios.l

2. A condenser comprising a frame, a rotor and asta-tor, the statorbeing divided in a plurality of condenser units insulated from eachother and spaced longitudinally of said rotor, and'means electricallyconnected with said rotor and interposedbetween adjacent condenser unitsfor shielding said units from effects of intercapacity couplingtherebetween.' v

3. A condenser comprising a frame, a rotor and a stator, thestator beingdivided in a plurality of condenser units insulated from each other andspaced longitudinally of said rotor, and7 meafns electrically' connectedwith said rotor and interposed between adjacent condenser units, saidmeans being independently adjustable toward and away from theirrespective unitsto vary the-incapacity ratios.

4. Inan apparatuspf the class described,

a -condenser comprising a frame, a plurality of stator units supported.on said frame in spaced relation and insulated from each other, a rotorcomprising a` plurality'of members each cooperating in capacitativerelation with said stator units, and balancing means mounted on saidrotor intermediate adjacent condenser units and adjustablelongitudinally of said rotor.

5. A variable capacity device comprising a plurality of condenser units,each unit having a rotor element and a stator element, common means foroperating the rotor ele-` ment of each unit, a ,conductive plate, inaddition to said elements, and means for supportingsaid plate betweensaid units and for adjusting` the same along the rotor axls.

6. A variable capacity device comprising same to said means.

8. A variable capacitydevice comprising a plurality of condenser units,each unit having a rotor element and a stator element, common means foroperating the rotor element of each unit, a pair of conductive plates,in addition to said elements, and means for sup orting said platesbetween said units and or adjusting the same along the rotor axisrelative to each other and to the said unit. y

9. A variable capacity device comprising a plurality of condenser units,each unit having a rotor element and a stator element, a commonmeanssupporting a similarone of said elements in each unit and a pair ofconductive plates between said elements and ad- `justably supported byfsaid common' means.

10. A variable, capacity device comprising a plurality of 'condenserseach having a vrotor and a "stator, common means foryoperating all saidrotors in unison, and Ya conductive plate interposed between thecondensers and\adjustably spaced along the common rotor axis from thestators thereof.

1l. A .multiple variable capacity device comprising a frame, a pluralityof stators carried in spaced relation by said frame, a shaft mounted forrotation in said frame,` a plurality of rotors carried by said shaft andeach cooperating. with a corresponding one of said stators to provide avariable capacity upon rotation of the shaft, thus constituting aplurality of condenser units, and additional condenser elements disposedbetween, and

4arranged to coo crate with, said condensers,

to shieldthem rom one another and adjustable -to vary slightly therelative capacities of the condensers.

l2. A condenser comprising a frame, a plurality of stator units spacedlongitudinally of said frame, yrotor units in capacitative relation withsaid statoi` units and mounted on a common shaft, each pair of `stator.and rotor units having cooperating surfaces in capacitative relationwitheach other of area substantially equal to cooperating surfaces oftheother pairs of stator and rotor units, and all of said capacity areasbeing variable in uniform decrements as said common rotor isrotated, andmeans,

associated with each pair of said rotor and stator units andelectrically common with one of said units, permitting relative movementof a capacitative area toward and away from a cooperating capacitativearea of the other unitin a directi vrparallel with the axis of rotationof said common rotor units, whereby the capacity ratios of said rotorand stator units may be independently varied,

ybut theV angular relation between each set of rotor and stator unitswill be uniform for all pairs thereof in any position of rotation ofsaidcommon rotor.l

Signed at Chicago this'25th day of June, 1924.

PAULA. oHAMBERLAIN.`

